A known problem that I myself experienced, when I logged into Facebook, after rebooting to complete the installation of WINE. A tool that aims at enabling windows programs to run on other platforms.
So, what actually happens is that WINE installs a number of Microsoft Fonts, and well, I guess, one of them happens to be on Facebook’s alternative fonts, (the default one being Lucida Grande, which is NOT included in the package installed by WINE).
The problem can be fixed by simply uninstalling the package ‘msttcorefonts.’ You can do this either via the ‘Ubuntu Software Center’, or the terminal.
To do this via the terminal, use:
sudo apt-get remove msttcorefonts